This is an activity about how the Sun can affect the Earth's atmosphere, specifically the ionosphere. Learners will use real data from a Sudden Ionosphere Disturbance Monitor, or SID Monitor, to identify the signatures in the graphed data that can...(View More) be used to determine the times of sunrise and sunset. Although the SID monitors are designed to detect SIDs caused by solar flares, they also detect the normal influence of solar X-rays and UV light during the day as well as cosmic rays at nighttime. There is a distinct shape to a 24-hour SID data graph, with unique shapes, or signatures, of the graph appearing at sunrise and sunset.This activity is part of the Research with Space Weather Monitor Data educators guide. Use of and access to a Stanford Solar Center SID monitor and the internet is encouraged but not required. Locations without a SID monitor can use sample data provided in the educators guide.(View Less)